This visualization displays the top 10 most populous countries in 2020 as horizontal bar charts, with population values formatted in billions and a crosshair line that follows the mouse. Built with Vue 2 and D3 v7, it uses `d3.csv` to load UN population data, `scaleBand` for the y-axis country categories, and `scaleLinear` for the x-axis population range. The SVG renders bars, tick marks, and axis labels, with a vertical line positioned via the `mousemove` event.